FXUS66 KMFR 110534

AFDMFR



Area Forecast Discussion

National Weather Service Medford OR

934 PM PST Wed Dec 10 2025



.DISCUSSION...Updated Aviation Discussion. 





&&



.AVIATION...11/06z TAFs...Widespread low ceilings and visibilities 

are present along the coast, including North Bend, with IFR/LIFR 

levels expected through Thursday morning. Then, expect clearing to 

VFR in the afternoon. Inland, there are areas of low clouds and fog 

in valleys west of the Cascades, including at Medford, Grants Pass 

and Montague. Low clouds with MVFR/IFR  are also developing in 

Umpqua Valley, including at Roseburg.  These conditions will persist 

through Thursday morning then are expected to improve to VFR between 

18-21z. Elsewhere, conditions are VFR. 



&&



.PREV DISCUSSION... /Issued 252 PM PST Wed Dec 10 2025/ 



DISCUSSION (Today through Tuesday)...



Key Points:



* Overall, minimal weather impacts through this weekend

* Mostly light rainfall chances expected through tonight  

    - No snow expected

* Next widespread chance for precipitation is early next week      

    - Could be as early as Sunday  

    - Snow: Snow levels are high 6,000+ ft               

        - Little to no snow accumulation expected     

    - Rain: Mainly for Coastal areas, Cascades, & Umpqua Basin

        - Highest chances for accumulation of at least 0.25"/24hrs 

    - Wind: Advisory level wind speeds possible early next week

        - Mainly eastside areas and Shasta Valley



Further Details:



Our weather across the PacNW continues to be dominated by an area

of low pressure over parts of northern British Columbia and high 

pressure off the coast of California. This setup is allowing for a

large swath of moisture advection into the region between these 

two features. By far and large, all the weather impacts continue 

to be north of our forecast area where considerable rainfall has 

resulted in significant river rises, especially across Washington.

In other words, we are only expecting light rainfall through 

Thursday morning given the location and strength of the high 

pressure. Eventually, the ridge of high pressure does break down, 

and the orientation shifts to allow this moisture plume to go 

farther north into Canada Thursday through Sunday. Through this 

stretch, we are expecting dry conditions. There continues to be 

uncertainty on the next potential area of low pressure impacting 

the region, but it could be as early as Sunday. Deterministic and 

ensemble members have a strong signal for rainfall chances 

increasing by Monday and continuing through at least middle of 

next week. Snow levels are really high early next week, and at 

this time very little snowfall is anticipated. Cluster analysis 

continues to show a split (ridge vs trough) with 5000mb heights 

early next week. This doesn't lead to high confidence with some of

the exact details. The probability for at least 0.50" of rainfall

over 24hrs is about 40%-80% with higher chances along/near the 

coast and Umpqua Basin with decreasing chances elsewhere inland. 

Very low chances (0%-30%) for these probabilities on the eastside.

The probability for at least 2.0" of snow over 24 hours is only 

around 25% Monday night through Tuesday night for the Cascades 

north of Highway 140. Furthermore, most ensemble members don't 

start accumulating snowfall until middle of next week. In other 

words, we still have some details to hash out, but early to middle

of next week does look to be the next potential active weather 

pattern. 



A note on Crater Lake snowfall: the latest Crater Lake has had 

zero snow depth was December 26th, 1976. Record keeping began in 

1919 for Crater Lake, and we have only had 9 years where we went 

into December for the last snow depth of zero. This will be the 

10th year, and will likely rank at least 3rd latest ever. In 1958,

we went until December 20th, and in 2008 we went until December 

11th. 





-Guerrero



MARINE...Updated 200 PM PST Wednesday, December 10, 2025...Seas 

remain hazardous to smaller crafts as high and steep swell 

persists this evening through tonight. Conditions improve Thursday

evening into the early weekend as high pressure builds and seas 

lower.



The next big weather concern will be around Monday as a low 

deepens out in the Pacific and models are showing a cold front 

swing through the waters to our north. Right now, southerly gales 

are looking more probable than not around 60 to 70 percent.



&&



.MFR WATCHES/WARNINGS/ADVISORIES...

OR...None.



CA...None.



PACIFIC COASTAL WATERS...Small Craft Advisory until 10 AM PST 

     Thursday for PZZ350-370. 



&&



$$